New Delhi: In a sweeping board shake-up, Edinburgh-based Cairn Energy Plc on Thursday announced that Bill Gammell will step down as Chief Executive Officer (CEO) of the company at the end of this month to become non-executive chairman.The oil explorer announced six role changes, including a step up for Simon Thomson, currently the Legal and Commercial Director at the company, to CEO, Cairn Energy said in an emailed press statement.Mike Watts will continue as Deputy Chief Executive and Finance Director Jann Brown will become Managing Director, reporting to Thomson.Murray, the Non-Executive Chairman since 2002, will stand down on July 1 and will be replaced by Gammell.Gammell's move from Chief Executive to Chairman is an unusual one in corporate governance terms. A former international rugby player for Scotland, Gammell led Cairn Energy at the time it discovered natural gas off the East Coast of India and then a major oilfield in Rajasthan.Cairn Energy said he will continue to lead negotiations on its planned sale of a majority stake in its Indian unit to London-listed mining group Vedanta Resources Plc.

"Bill will continue as Chairman of Cairn India and will retain overall responsibility for the current Vedanta transaction," it said.Malcolm Thoms, Chief Operating Officer, and Philip Tracy, Group Engineering and Operations Director, will step down from the board, as will current Chairman Norman Murray. The changes take effect on July 1, Cairn said.The board, led by the senior independent director, Iain McLaren, views Sir Bill as overwhelmingly the best choice for Chairman," said Murray."His 30 years in the oil and gas industry, coupled with his knowledge and understanding of operations in South Asia and his experience as chairman of the publicly listed Cairn India, are a unique resource for the company. Separately, Cairn India said Malcolm Thorns, a representative of parent firm Cairn Energy Plc, has stepped down from the board of directors of the company with effect from June 15."Cairn Energy Plc will continue to be represented on the board by Sir Bill Gammell, Chairman, and Jann Brown," it said in a statementFurthermore, Rick Bott, Executive Director & Chief Operating Officer, has also ceased to be a director of the company, although he continues to be associated with the Cairn India Group in his capacity as Executive Director and Deputy CEO of Cairn Energy India Pty Ltd, a wholly owned subsidiary of the company, it added.